PB2269: HUMORAL AND T-CELL RESPONSES TO SARS-COV2 VACCINATION IN PATIENTS WITH MULTIPLE MYELOMA MANAGED IN THE COMMUNITY SETTING
Authors: H. Holik, I. Krečak, I. Vučinić Ljubičić, L. Cvetko Krajinović, A. Požgain, I. Čabraja, L. Vinković, B. Halassy, S. Mitrović, B. Coha
Journal: HemaSphere (2022)

Background: Multiple myeloma (MM) is a plasma cell neoplasm with an impaired humoral and cellular immune system, mostly due to underlying disease and treatment. Approximately one-third of MM patients dies from coronavirus disease 2019 (COVID-19). Vaccines can provide significant protection against COVID-19 but seroconversion and protection in MM patients with MM is lower than that in the healthy population. For this reason, there is an unmet need to identify MM patients at high risk of COVID-19-related morbidity and mortality. Aims: To investigate specific humoral and T-cell response patterns to SARS-CoV2 vaccination in MM patients treated in the community setting. Methods: This was a single-center study conducted at dr. Josip Benčević General Hospital, Slavonski Brod, Croatia. Consecutive patients with multiple myeloma vaccinated against COVID-19 were prospectively included in the study. Humoral and celullar responses were determined by live virus neutralization test (with a negative result being <4 IU/mL) and QuantiFERON SARS-CoV-2 Ag1/Ag2, Qiagen (test being positive or negative), respectively. The chi-squared and the Mann-Whitney U tests were used. Statistics were performed with MedCalc Statistical Software® (Ostend, Belgium, v. 20.014) Results: A total of 17 patients with active MM were included; median age was 65 years (range 53-85), 35.3% were female and 5 (29.4%), 52.9% and 3 (17.6%) of patients had International Staging System (ISS) stages of 1, 2, and 3, respectively. Eleven patients (64.7%) were screened during first line/maintenance treatment (mostly bortezomib-based=10) and six (35.2%) in the relapsed setting (mostly daratumumab-based=4). Ten patients (56%) were previously autotransplanted, six using a tandem approach. Three patients (17.6%) previously recovered from COVID-19. Eleven patients (64.7%) received at least two doses of mRNA-based vaccines and six (35.3%) were fully vaccinated with vector-based vaccines. A total of eleven (64.7%) and six (33.3%) patients had humoral and T-cell responses, respectively; however, responses were not correlated (p=0.408). On the other hand, more mRNA-vaccinated patients achieved humoral (81.8% vs. 33.3%; p=0.050) response, whereas there was no difference with respect to cellular response (27.3% vs. 33.3%; p=0.799). Age, sex, ISS stage, line of treatment and prior SARS-CoV2 infection were not associated with humoral or cellular responses (p>0.050 for all analyses). Interestingly, both humoral (72.7% vs. 27.3%; p=0.031) and cellular responses (100% vs. 0%; p=0.014) were more frequent in transplanted patients. The median follow-up was two months and two patients (11.7%) developed COVID-19, both had no humoral (p=0.048) or cellular (p=0.345) response to previous vaccination. Summary/Conclusion: This data acquired in the community setting demonstrate low T cell response rates and better humoral response rates to SARS-CoV2 vaccination in actively treated MM patients. Better responses were seen with mRNA-based vaccines and in transplanted patients, indicating that mRNA vaccines and stem cell transplantation may provide higher stimuli to the immune system and provide higher disease control and better immune reconstitution, respectively. Two patients without humoral and T cell responses contracted COVID-19, emphasizing the need for vaccination against SARS-CoV2 in order to protect this highly vulnerable population. Limitations of the study are its small sample size and single-center design.